Lethargic Non eating clowns

[blureef1]

I have two of Rods onyx clowns. I've had them about 10-11 months I believe. The last 2 days one of them (the smaller of the two) has been lethargic and hasn't eaten. Today he looked at food a little as it floated by but seemed disinterested. He just kind of hangs out at the top in the corner. He kind of does this anyways normally, but he definetely seems less active. The bigger one does not seem to be picking on him or anything. Everything else in the tank looks and acts fine and feeds as normal.

I did a water change today (5 gallons on a 50). I may do another one tomorrow.

Anyone have any others suggestions?

[reefman13]

What are tank parameters?

Is there any size difference between them?

Any discoloration, or absolutely anything different in the physical appearance?

Stringy poop?

Have you tried any brine?

[blureef1]

Water conditions seem OK.

The one that is not eating is the smaller of the two clowns. Ever since I got them he has been a little smaller. The bigger one has grown more and fattened up more in the time that I have had them.

There are no other physical issues.\ I can see. He looks like he always looked, he just doesn't eat and isn't as active.

One other thing I've noticed is that, the two clowns usually sleep together snuggled up next to each other in the same part of the tank at night. The last two nights the little guy has been off on his own in a different spot while the bigger guy is in the normal place. They hang near each other when the lights are on, but the little guy doesn't follow the other one around nearly as much.

I feed Rods food, and occasionally a couple types of flake.

[blureef1]

His activity level has seemed to increase a little today. He is hanging out more with the larger clown and is hanging out in the middle of the tank more. I have noticed however that he has a large mass protruding from his vent area. This wasn't there a couple of hours ago. Is it possible he is constipated and trying to poop something out?

[Newreeflady]

*bump*

Good luck!

[blureef1]

He passed what ever was hanging from his vent. Seems a lot happier now. More energy and is eating. So I guess he just ate something that he couldn't quite digest well enough.